talbot



F. A. TALBOT 2,732,453

CONTACTQR RESISTING OPENING IN RESPONSE TO CURRENT SURGES Jan. 24, 19562 Sheets-Sheet 1 Filed Feb. 29, 1952 F. A. TALBOT Jan. 24, 1956CONTACTOR RESISTING OPENING IN RESPONSE TO CURRENT SURGES 2 Sheets-Sheet2 Filed Feb. 29, 1952 fil tam United States Patent CONTACTOR RESISTINGOPENING IN RESPONSE TO CURRENT SURGES Frank A. Talbot, New York, N. Y.

Application February 29, 1952, Serial No. 274,209

9 Claims. (Cl. 200-87) The present invention relates to a circuit makingand breaking device of the type adapted to be closed by remote controland the invention more specifically per tains to such a switch mechanismwherein the contacts are releasably maintained in a closed position andso constructed that surges in the load current assist in maintaining thecontacts in a closed position.

In a conventional contactor the closed contacts often open whenrelatively large current surges pass through the closed contacts. Amarked and rapid increase in the current sets up an intense magneticfield in the presence of the contacts and the flux often reacts in sucha manner as to move the contacts to an open position.

An object of the present invention is to provide a contactor wherein themovable contact in closing first engages a stationary contact and thenis moved linearly into engagement with another contact which serves as adetent to maintain the movable contact in engagement with the stationarycontact and to thereby prevent inadvertent opening of the contacts as aresult of a heavy current surge.

Another object of the invention is to provide a detent arrangement forreleasably maintaining the movable contact of the switch in engagementwith the stationary contact includingmeans for increasing the holdingaction in response to sudden increases in the current flowing throughthe closed contacts.

A further object of the invention is to provide a shock resistant remotecontrol contactor wherein one contact first engages another and thenslides therealong to insure good electrical contact between the engagedcontacts and to provide a loop circuit for the load current so that theflux set up thereby reacts in such a manner as to assist in maintainingthe contacts in the closed position.

A still further object of the invention includes means for insuringproper closing of the contacts in the event of failure of one of theelements employed in normal closing of the contacts.

Other objects and features of the invention will'be readily appreciatedand become apparent to those skilled in the art as the presentdisclosure proceeds and upon consideration of the accompanying drawingsand the following detailed description wherein an exemplary embodimentof the invention is disclosed.

In the drawings:

Fig. 1 isa front elevational view of a contactor exhibiting theinvention.

Fig. 2 is a sectional view taken on the line 2-2 of Fig. 1 showing theparts in the fully closed position of the switch mechanism.

Fig. 3 is a similar sectional view showing the elements in the fullyopen position of the contacts.

Fig. 4 is a similar sectional view showing the parts in an intermediateposition betweenthe open and closed positions of the contacts.

Fig. 5 is a perspective view of an element of the magnetic blow-outassembly.

The contactor is adapted to be mounted on a board 2,732.453 PatentedJan. 24, 1956 formed of insulating material such as employed in switchboards or the like. A mechanism for moving the c0ntacts to a closedposition is shown generally at 11 in Fig. 1 which includes a magneticcore 14 mounted on the board 10 and a coil 16 therefor and an armature12. A link 17 is connected to the armature and extends downwardlytherefrom. The link 17 is pivotally connected at its lower end to ahorizontally disposed arm 18 rigidly secured to a shaft 19. The shaft 19is journalled for rotation in bearings carried by the mounting board 10one of which is shown at 21. The shaft 19 may be utilized for actuatingany number of contactor units mounted on the board 10 in side-by-siderelationship. One of such units only is shown in the drawings. In Fig. 1the mounting board is shown broken at 20 but may be extended at this endto accommodate additional contactor units all actuated by the shaft 19.A sleeve 22 is provided surrounding the shaft 19 between the arm 18 andan actuating member 23 for the first contactor unit. A similar sleeve 24(shown in part) embraces the shaft 19. One end of the sleeve 22 abutsagainst one side of the actuating member 23 and an end of the sleeve 24engages the other side face of the member 23 to maintain the actuatingmember 23 in a substantially fixed position axially of the shaft 19.

The actuating member 23 is preferably formed of insulating material andprovides means for supporting and carrying a movable contact element 26.One terminal for the switch mechanism is shown at 27 which may besecured to the board 10 by means of a screw 28. A flexible conductor 29is maintained in electrical circuit relationship with the terminal strip27 by means of the screw 28. The flexible conductor 29 may be formed oflaminations as illustrated or may be of any other type having flexiblecharacteristics. The upper end of the conductor 29 carries a rigidconductive portion 31 which is arranged under and in engagement with thecontact 26. The contact 26 and the end of the conductor 29 are securedin this position and mounted on the actuating member 23 by means of abolt 32.

The actuating member 23 is provided with an elongated or generallyelliptical shaped opening for receiving the shaft 19. The upper portionis circular shaped as indicated at 33 and is struck about a horizontalaxis having a radius substantially equal to that of the shaft -19. Thelower portion of the elongated opening is also arcuate shaped asindicated in Fig. 3. The axis about which the lower arcuate edge of theelongated slot is struck is spaced below the axis about which the curvedsurface 33 is generated. A lateral slot 36 is also provided in theactuating member 23 which is in open communication with-an intermediateportion of the clot:- gated opening. A key 37 carried by the shaft 19extends into the lateral slot 36. The slot 36 is provided with angularconverging side walls as will be evident upon consideration of Fig. 2. Arecess is provided in the actuating member 23 below the opening for theshaft 19 for accommodating a helical spring 25. The lower end of thespring abuts against the closed end of the recess. A shoe 34 is engagedby the upper end of the spring 25. The shoe has a concave surface forengaging the periphery of the shaft 19. The spring may be introducedinto the recess through an aperture indicated in dotted lines in Figs. 3and 4.

A stationary contact which serves as a fixed abutment is shown at 38. Anelectrically conductive arm 45 supports the contact 38. The arm 45 issecured to the board 1.0 by means of a screw 39. A circuit isestablished from the stationary contact 38 to a terminal strip 41through a conductive spacer element 42 and one terminal 43 of a blow-outcoil and a washer or the like 44 interposed between the supporting arm45 and the terminal end 43 of the blow-out coil. These parts aremaintained in rigid assembled relationship to establish a goodelectrical circuit between the contact 33, the terminal end 43 of theblow-out coil and the terminal strip 41 by the screw 39. The upper endof the terminal strip 41 is provided with an opening 46 for connectingan electric conductor thereto.

A detent is provided for the purpose of releasably retaining the movablecontact 26 in engagement with the contact 38. The detent includes acontact element 47 which is rigidly secured to one arm of a bell cranklever 48 by means of a screw 56 and a cylindrical shaped spacer element76. The lever 43 is mounted for pivoting movement about a pin 49 carriedby the side boards 62 and 63 of an arc shield assembly. The bell cranklever 43 is formed of a metal having good electrical conductivecharacteristics and the upper end 51 is rigidly secured to one end of aflexible U-shaped loop 52. The other end 53 of the U-shaped loop 52 ismaintained in a fixed position and electrically connected to anotherterminal 57 of the blow-out coil 40. The upper end 53 of the U-shapedloop 52 is maintained in a fixed position by means of a bolt 56 whichextends through the laminations and through the terminal end 57 of theblowout coil. The bolt 56 is anchored in a block of insulating material58 rigidly secured in position by means of a bolt 61.

The are shield side boards 62 and 63 are formed of heat resistantmaterial. These side boards are arranged at opposite sides of thecontacts and maintained in spaced relationship. One spacer element forthis purpose is shown at 66. Another spacer element 67 is bar-shaped andformed of insulating material. The block 58 also serves as a spacerelement for the side boards and a block 6.8 formed of insulatingmaterial serves as a further spacer element. The block 68 is secured tothe conductive member 42 by means of a screw 69. A plurality of bolts 71extend through the various spacer elements and nuts at the outer facesof the side boards 62 and 63 hold them in position to provide arcshields at the sides of the contacts.

The bar shaped insulating member 67 is rigidly secured between the sideboards 62 and 63 by two bolts 71. The member 67 serves as an abutmentfor a spring 73 which cooperates with the contact 47. The upper end ofthe spring 73 extends into a cylindrical shaped recess formed in theinsulating member 67. The spring 73 at its lower end engages the upperface of one arm of the bell crank lever 43 and thus tends to rotate thislever in a clockwise direction about the pivot pin 49. Such pivotingmovement of the bell crank lever 48 is limited by means of an adjustableabutment screw 77 carried by an extension 78 of the insulating block 67.The position of the end of the abuternent screw 77 may be adjusted andfixed by means of the lock nut 79.

r The blow-out coil 40 is provided with a magnetic core This coreextends through openings (notshown) in the side boards 62 and 63. Aplate 82 lies in flat engagement with one end of the core 81 and extendsalong the outer face of the side board 62. The free end 83 is bentinward and extends into a notch formed in the side board 62. A similarplate 84 lies in fiat engagement with the other end of the magnetic core81 and extends along the outer face of the side board 63. The free end36 of the plate 34 extends into a notch in the side board 63. The plates82 and 84 are formed of magnetic material and the free ends 83 and 86are turned inwardly to provide a relatively narrow air gap forstretching the arc in a conventional manner upon the opening of thecontacts. The plates 82 and 84 may be secured to opposite ends of thecore 81 by screws one of which is shown at 85.

In operation and when the switch is in the open position shown in fig. 3energization of the coil 16'will cause the armature 12 to move. upwardlyand rotate the shaft 1 9 in a counter-clockwise direction from thatshown in Fig. 3. In this position the spring 25 will maintain theactuating member 23 in a lower position so that the arcuate edge 33 willbe in engagement with the periphery of the shaft 19. Counter-clockwiserotation of the shaft 19 will cause the key 37 to engage the upper edgeof the lateral slot 36 so that the actuating member 23 is then rotatedin a counterclockwise direction. The movable contact 26 is thus movedinto engagement with the fixed contact 38. This position is shown inFig. 4.

The contact 38 thereafter serves the further function of acting as anabutment preventing further counter-clockwise rotation of the contact26. Further counter-clockwise rotation of the shaft 19 is possiblebecause of the particular disposition of the key 37 and such rotationwill cause the actuating member 23 to move upwardly from the positionshown in Fig. 4 so that the contact 26 while being pressed intoengagement with the contact 38 slides therealong to further develop goodelectrical contact. The face 87 of the contact 26 is angularly disposedwith respect to the surface engaging the contact 38 and during upwardmovement the face 87 engages the face 88 of the substantially stationarydetent contact 47. During such linear movement of the actuating member23 from the position of Fig. 4 to the position shown in Fig. 2 thespring 25 is compressed so that the shaft 19 then enters the lowerportion of the elongated opening in the actuating member 23. The contact26 is thus urged into firm engagement with the detent contact 47 andcounter-clockwise swinging of the contact 47 is resisted by the spring73 and the resilient characteristics of the U-shaped loop 52. A circuitis thus established from the terminal 27 through the flexible conductor29, the contact 26, the contact 47, the bell crank lever 48, theU-shaped loop 52, the blow-out coil 40, the spacer element 42, and theterminal strip 41. Another circuit is established from the contact 26throughthe contact 38 and the washer 44 and the element 42 to theterminal strip 41.

The invention includes auxiliary means to insure closing of thecontactor in the event of breakage or failure of the spring 25. Anarcuate edge 91 is provided on the actuating member 23 as shown in Fig.3. This edge is struck about an axis defined by the center of the shaft19 when the parts are in the position shown in Fig. 3. The radius of thesurface 91 is such that it clears the lower end of an extension 92 ofthe conductive arm which supports the stationary contact 38. Thus thearcuate end 33 ofthe elongated opening in the actuating member 23 ismaintained in engagement with the periphery of the shaft 19. duringinitial swinging movement of the actuating arm 23 towards the closedposition from that shown in Fig. 3. A notch 94 is provided in the upperportion of the actuating member 23 to permit upward movement thereofafter the movable contact 26 engages the fixed contact 38 and when theparts are in the position shown in Fig. 4. Thus closing of the contactoris assured even though there is a failure of the spring 25.

The operation of opening the contactor involves deenergization of thecoil 16. The armature 12 then moves downwardly so that the shaft 19rotates in a clockwise direction from the position shown in Fig. 2. Thekey 37 first moves the actuating member 23 downwardly and the contact 26slides downwardly along the face of the stationary contact 38. The upperend of the contact 26 thereby escapes from under the detent contact 47.Furtherclockwise rotation of the shaft 19 will then permit the actuatingmember to swing to the open position shown in Fig. 3.

The switch mechanism has particular utility'in resisting inadvertentopening of the contacts upon the occurrence of heavy surges in the loadcurrent passing through the closed contacts. The latch arrangement asprovided by he detent m act 7 m y be f icient. o, p e n {separation ofthe contacts 26 and 33 and the contacts 7 nd 26- h e en a iamq s l sticfof m n ai ng] h contacts in a closed position is further supplemented bythe action of the currentfiowing' through the U -shaped loop 52. A heavysurge current passing through this U-shaped conductor sets up a flux inone leg of the U- shaped member which opposes the flux set up around theother leg. The upper end 96 of the U-shaped member is thus moved to theright as a result of this magnetic field which tends to straighten theconductor. Accordingly the bell crank lever 48 is turned in a clockwisedirection about the pin 49. Thus the detent contact 47 is moveddownwardly to more positively maintain the movable contact 26 inengagement with the stationary contact 38. The area of overlapping isincreased and the pressure of engagement is also increased.

When the contacts open under load the fleld set up by the blow-out'coil40 provides flux linking the free ends 83 and 86 of the magnetic platesassociated with the blow-out coil. Thus the arcis stretched from thecontact 47 to the contact 26 as shown in a dotted line 98 in Fig. 3.Such elongation and stretching of the arc is accomplished in awell-known manner for the purpose of minimizing the burning of thecontacts.

While the invention has been shown and described with reference tospecific structural features and in connection. with one generalorganization for biasing a detent contact to a position to furtherprevent the separation of the contacts it will be appreciated thatchanges may be made in the elements as well as the overall assembly.Such modifications and others may be made without departing from thespirit and scope of the invention as set forth in the appended claims.

What I claim and desire to secure by Letters Patent is:

1. In an electrical switch, a stationary abutment contact, a swingablearm carrying a movable contact adapted to swing to a position engagingsaid abutment contact, a shiftable detent contact engaging said movablecontact on a side substantially opposite said abutment contact, aflexible U-shaped electrically conductive member mechanically connectedto said detent contact and in circuit relationship therewith to shiftthe detent contact into more positive engagement to cause increasedcontact pressure beween the movable contact and said abutment contactupon the occurrence of current surge through the U-shaped conductivemember.

2. In a remote control contactor, a stationary contact, a rotatableshaft, an actuating member having an elongated opening therein receivingsaid shaft, means resiliently urging the actuating member radially ofthe shaft, 21 second contact on said actuating member, a key carried bythe shaft projecting into a slot extending from the elongated openingswinging the actuating member upon initial rotation of the shaft andmoving the second contact into engagement with the stationary contact,said key being disposed to move the acuating member radially of theshaft in opposition to said resilient means upon further rotation of theshaft to shift the second contact linearly along the staionary contact,and a detent engaged by the second contact while maintaining engagementwith the stationary contact.

3. In a remote control switch, a fixed contact, a rotatable shaft, anactuating member mounted on said shaft having an elongated openingtherein, a spring urging the actuating member radially of the shaft sothat one end of the elongated opening engages the periphery of theshaft, a second contact carried by said actuating member, a key securedto the shaft extending into a slot in the actuating member to turn theactuating member upon initial rotation of the shaft and move the secondcontact into engagement with the fixed contact, said key being soarranged to move the actuating member radially of the shaft inopposition to the spring upon further rotation of the shaft to shift thesecond contact linearly along the stationary contact while being pressedthere against, and a detent engaged by the second contact aferpredetermined linear movement thereof.

4. In a remote control contactor, a stationary contact, a rotatableshaft, an actuating member having an elongated opening therein receivingsaid shaft, resilient means urging the actuating member radially of theshaft, a secand contact on said actuating member, a key carried by theshaft to turn the actuating member upon initial rotation of the shaftand move the second contact into engagement with the stationary contact,said key moving the actuating member radially of the shaft in oppositionto said resilient means upon further rotation of the shaft to shift thesecond contact linearly over the stationary contact, a detent contactmounted for pivoting movement and adapted to be engaged by the secondcontact after a predetermined linear movement thereof, a U-shapedelectrically conductive loop having one end mounted in a fixed position,an electrically conductive lever connected to the other end of theU-shaped loop and to the detent contact so that flux set up by U-shapedloop pivots the detent contractor into further engagement with thesecond contact.

5. In an electrical switch, a stationary contact forming a fixedabutment, a rotable shaft, a rigid actuating member mounted on saidshaft to rotate therewith and movable radially with respect to theshaft, a contact carried by said actuating member adapted to engage thestationary contact upon predetermined rotation of the shaft and swingingmovement of the actuating member, means operated by the shaft moving theactuating member radially with respect to the shaft upon furtherrotation thereof to urge the movable contact into engagement with thestationary contact and to shift the movable contact linearly along thestationary contact, a detent contact engaged by the movable contactafter a predetermined linear movement thereof, a U-shaped flexibleconductive loop in circuit relationship with the detent contact andmechanically connected thereto to urge the detent contact to a positionfurther overlying said movable contact in response to current surgespassing through the U- shaped loop.

6. In an electrical switch, a stationary contact, a movable contactengaging the stationary contact, a detent contact engaging and overlyinga portion of said movable contact holding it in engagement with saidstationary contact, a U-shaped flexible conductive loop in circuitrelationship with said detent contact and mechanically connected theretoto urge the detent contact to a position causing a greater overlap ofsaid portion of the movable contact in response to current surgespassing through the U-shaped conductive loop.

7. In an electrical switch, an abutment contact, a rigid swingable armcarrying a movable contact thereon adapted to move in a circular path toswing the movable contact to a position engaging said abutment contact,a pivotally mounted bell crank lever, a detent contact carried by an armof the bell crank lever overlying and engaging said movable contactholding it in engagement with said abutment contact, a flexible U-shapedelectrically conductive loop having one leg electrically andmechanically connected to another arm of the bell crank lever, meansproviding a rigid support for a second leg of the U-shaped conductiveloop, a circuit extending from the second leg of the U-shaped loopwhereby the bell crank lever is pivoted to shift the detent contact to aposition increasing the overlying engagement of the detent contact withthe movable contact and increasing the pressure between the movablecontact and the abutment contact upon occurrence of a current surgethrough the U-shaped loop.

8. In an electric switch, a stationary contact, a rotatable shaft, anactuating member mounted on said shaft for rotation therewith, a secondcontact carried by the actuating member movable into engagement with thestationary contact upon rotation of the shaft and swinging movement ofthe actuating member, said actuating member having an opening thereinelongated radially of the shaft, an arcuate surface on the actuatingmember concentric with the axis of said shaft, fixed means adjacent saidarcuate surface preventing radial shifting of the actuating memberrelative to the shaft during the swinging movement of the second contactinto engagement with the stationary contact, means for moving theactuating member radially of the shaft and shifting the second contactlinearly along the stationary contact, and a detent engaged bythe secondcontact after a predetermined linear movement thereof.

9. In an electric switch, a stationary contact, an actuating membermounted to rotate about one axis, a second contact carried by theactuating member movable in an arcuate path into engagement with thestationary contact upon swinging movement of the actuating member aboutsaid axis, said actuating member being movable transversely of saidaxis, an arcuate surface on the actuating member concentric with saidaxis, means adjacent said arcuate surface preventing shifting of theactuating member transversely of said axis during said swinging movementof the second contact into engagement with. the stationary contact,means for moving the actuating memher transversely of said axis whilepressing the second contact into engagement with the stationary contact"and shifting it linearly thereover, and a detent engaged by the secondcontact after a predetermined linear movement thereof.

References Cited in the file of this patent UNITED STATES PATENTS SmithApr. 17, 1917 1,395,348 MacNeill Nov. 1, 1921 1,452,333 Alter Apr. 17,1923 1,764,369 Van Sickle June 17, 1 930 1,768,536 Ainsworth July 1,1930 1,804,628 MacNeill May 12, 1931 1,819,831 Whalen Au. 18, 19311,949,018 Koppitz Feb. 27 1934 1,962,293 Bowie June 12, 1934 2,064,6576011 a Dec. 15, 1936 2,127,813 Graves, Jr. Aug. 23, 1938

